The present invention relates to a card reader apparatus for receiving an inserted prepaid card therein to read balance information and, more particularly, a card reader apparatus for detecting the position of a punch hole formed in a prepaid card to read balance information.
FIG. 6 shows a conventional magnetic card reader/writer apparatus for magnetically recording/reading information from/on a prepaid card on which total information corresponding to a prepaid amount is recorded. Referring to FIG. 6, reference numeral 1 denotes an apparatus main body; 2, an insertion port in which a prepaid card is to be inserted; and 3, a prepaid card (to be referred to as a card hereinafter). In the above arrangement, when the card 3 is inserted in the insertion port 2, the inserted card 3 is detected by an insertion detection sensor 11. In this case, in the apparatus main body 1, when a motor (not shown) is started, and rollers 12 driven by the motor are rotated, the card 3 is conveyed in a convey path 14 by a convey belt 13.
In order to visually indicate balance information on the card 3, a punch hole is formed at a position corresponding to balance information with a decrease in balance information.
More specifically, when a punch hole detection sensor 15 arranged in the convey path 14 detects a punch hole formed in the card 3 conveyed in the convey path 14 to represent the balance of the card 3, and the card 3 is determined as a valid card having a balance, the card 3 is further conveyed to the position of a magnetic head 16 arranged in the convey path 14 like the punch hole detection sensor 15. The magnetic head 16 reads the balance information, of the card, magnetically recorded on a magnetic track (not shown) of the card 3.
At this time, when the read information is proper, and the card 3 has a balance, the card 3 is determined to be used for purchasing an article. When the article is purchased, a balance obtained by settling the charge for the article is recorded on the card 3, a punching unit 17 forms a punch hole at a punch position corresponding to the new balance of the card 3, and the card 3 is returned.
FIG. 7 shows a punch hole portion 31 of the card 3 punched by the punching unit 17. Punch holes are formed at positions corresponding to balances indicated by numbers 0 to 9 of the card 3. More specifically, in an unused card, no punch hole is formed at a position corresponding to any number. In this case, when the card 3 is used by, e.g., one unit amount, a punch hole is formed at the position corresponding to the number 9. Thereafter, punch holes are sequentially formed at the positions corresponding to the numbers 8 to 1 in accordance with use of the card 3. When the card 3 is used, and the balance of the card 3 becomes zero, a punch hole is formed at the position corresponding to the last number 0. As a result, the card 3 is determined as an invalid card.
When the card 3 having a punch hole is inserted into the apparatus main body 1, the apparatus conveys the card 3 at a predetermined speed, the leading end portion of the card 3 is detected by the punch hole detection sensor 15. Subsequently, a detection output from the punch hole detection sensor 15 is sampled/input at a predetermined time interval. As shown in FIG. 8A, sampling results are sequentially stored in a buffer (not shown) from the sampling result of punch hole data at the position corresponding to the number 9 of the leading end portion of the card. In the example in FIG. 8A, reference symbols a and b respectively denote the storage areas of sampling data corresponding to the leading end portion (number 9 side) and the trailing end (number 0 side). In addition, "1" denotes punch hole data. The punch hole data corresponding to the numbers 9 and 8 of the punch hole portion 31 are stored in areas c and d of the buffer, respectively. Note that "0"s of the area a to the area immediately before the area c represent the sampling result of an edge area extending from the leading end of the card 3 to the punch hole portion 31, "0"s between the areas c and d represent the sampling result of an interval area between the numbers 9 and 8.
However, after the card 3 is inserted in the insertion port 2, when the card 3 is not properly received into the apparatus because a user temporarily holds the trailing end portion of the card 3 with his/her fingers against a convey force, the punch hole data of the card 3 is stored in the buffer like the data shown in FIGS. 8B and 8C. Such a phenomenon occurs when, in an apparatus having a small depth and the punch hole detection sensor 15 arranged near the insertion port, a user performs a wrong operation such that the information of the card 3 is read while the user inserts the card 3 and keeps holding the trailing end portion of the card 3. The apparatus recognizes, as an illegal card, the card 3 inserted by the above operation. For this reason, the utilization efficiency of the apparatus is degraded, and the apparatus is unpopular among users.
More specifically, when the card 3 is temporarily held by the insertion port 2, punch hole data, of the numbers 9 and 8, to be stored in the areas c and d as shown in FIG. 8A are stored in the areas d and e in FIG. 8B, and are stored in the areas c and e in FIG. 8C. That is, balance information different from that of an actual punch position is stored in the buffer. For this reason, balance information based on the punch hole data read from the buffer does not coincide with balance information constituted by magnetic information read from the card 3. As a result, the card 3 is disadvantageously returned as an illegal card (counterfeit card).